If you get a CEREC crown to cover a discolored tooth, you want to make sure that the crown itself isn’t going to become stained. We have some good news for you: the material used for making CEREC crowns is highly resistant to staining, much more resistant than tooth-colored fillings made of composite resin.
We’ve always known about the stain resistance of these materials, but now a new study allows us to categorize just how stain resistant CEREC materials are.
How to Measure Discoloration
One of the key questions for a study like this is figuring out how to measure discoloration. For tooth restorations and materials like ceramic tile, we use a parameter called ∆E. It works, but it’s kind of a technical measure, so it’s hard to communicate what it really means. Fortunately, some people have dones studies in the past to determine what level of ∆E can be distinguished by people and at what level it becomes unattractive discoloration. The perceptibility threshold (the point at which 50% of people can tell there’s a color difference) for ∆E is 1.2. We call this the PT. The acceptability threshold (the point at which 50% of people will say that two objects are unacceptably different in color) for ∆E is 2.7. We call this AT.
Testing Discoloration with Coffee
Researchers wanted to see how much coffee could stain the materials used for CEREC restorations. Coffee is a good choice: it’s a highly staining liquid that is widely consumed around the world. To test the discoloration effect, researchers soaked samples of eight different types of CEREC blocks in coffee for one day, one week, and one month. These CEREC blocks included composite resin, hybrid ceramic, PMMA, and feldspathic ceramic materials. They also soaked composite resin fillings for comparison. Then they tested whether polishing could remove discoloration experienced by the materials.
Here are the ∆E values for different types of materials:
|Soaked in Coffee 1 Day||1 Week||1 Month||Polished after 1 Month|
|Composite Resin Block||1.1||1.86||2.9||1.3|
|Hybrid Ceramic Block||0.5||0.8||1.4||0.5|
|Feldspathic Ceramic Block||0.3||1.1||1.8||0.3|
|Conventional Composite Resin Filling||1.5||2.9||4.8||2.8|
Remember, when it comes to ∆E, most people can’t distinguish a difference smaller than 1.2, and they think that any difference less than 2.7 is acceptably the same color.
How Does This Translate to Your Experience?
The basic study shows us which restorations are most stain resistant, but we still have to translate the results a bit to put it in terms that make sense for your actual experience. None of us go home and actually take our crowns out to soak them in coffee. So how does soaking in coffee compare to someone actually drinking coffee?
If we assume that a person drinks an average number of cups of coffee for an American (3.1), and that for each cup of coffee you drink, coffee stays in contact with your teeth for about 15 minutes, then the average American gets about 47 minutes of direct coffee exposure per day. That means that one day of soaking in coffee is about the equivalent of 31 days of actual coffee drinking experience, one week equals seven months of coffee drinking, and one month of coffee soaking is the equivalent of about two and a half years of coffee drinking.
In other words, people with ceramic CEREC restorations (hybrid or feldspathic) would likely not notice a discoloration of their restorations between their regular checkups, and routine polishing should keep them looking bright for their entire lifetime.
Plastic restorations, whether composite resin or PMMA would become noticeably discolored, although with polishing, the CEREC restorations would be barely discolored to the naked eye.
Are You Tired of Stained Fillings?
If you got composite resin fillings to avoid having visible fillings, you’re probably disappointed if they became stained. Fortunately, we offer CEREC fillings that are highly stain resistant and can stay bright and attractive for life.